Pisound Zynthian MCP

looking after https://discourse.zynthian.org/t/build-with-pisound-and-mcp23017/3315

it appears this dude knew much more than I know what im doing, as others pointed him in the direction, and he took care of business… I think I may need a bit more hand holding, but Im esentially using the same basis as that dude. I got a PI4, a pisound, a mcp23017, and some ky040 encoders (read that these have a resistor in there)

i know ill jump in the webconf once i make the connections, but i looked over the allinone schematic and some of it makes sense, and some doesnt since this is my first foot into rolling my own build. when looking at that mcp diagram, what is inta intb? all thes encoders have a ground, can it all share the same ground pin? pin 7 8 27 28 go to sw1 (what is sw1 and sw-1)? vcc and reset goes to a c4 (whats a c4 other than an explosive? goin to a 100n (i guess its a resistor?)

So i can probably take a picture of this lot of PI stuff I bought, but i dont know what half of it would be useful. I do have a small 3.5 lcd, and a 7inch waveshare, and 7inch official pi display, but doesnt these displays also have to connect to the MCP?

since im an idiot, I will surely make a thorough post if I ever get this all working. this way the next idiot can do it with less assistance than i, and of course a brief sound and many pictures once its all done.

This was the blog that got me started on my DIY zynth. Lots has changed, although you could still build this same version now.

Learning how to read schematics is invaluable here.

So I’m trying to find that allinone schematic, and I think I’ve found one from 2019… I’m afraid if I start soldering, there is probably a more up to date schematic for the mcp23017.

Looking through a box of pi stuff I bought on eBay, I’ve located two of the mcp23017 that I lifted from the breadboard.
Since I have the ky040 encoders with some resistor on there, what should I do? The allinone has scl and sda, what are those? Also what is the inta and intb? Also is that vcc and reset going right to the 5v header on the pi? It looks like there is also a lead from both of them going to a C4 and 100n to the ground? Can someone link me where I buy some c4 and 100n?

Also can you give me a quick rundown what is the c4 and 100n? And why are the ky040 resistors a problem with the schematic. I plan on seeing this out, I just don’t want to fry anything

Hi @slimpyman !

You have all official HW files in the zynthian-hw repository:

This repo contains kicad & gerber files for all the official boards.


I’m looking through that GitHub page you linked… Those kcad and Gerber files are just for 3d prints right? I’m trying to learn to walk before I run; I don’t care about the 3d case until I know everything is working. Looking in the allinone link expands to like 30 items, and not familiar with any of those file extensions, and the pdf and jpg files are just a picture of components like the hifiberry and stuff with just an arbitrary line connecting them. I don’t see any files named mcp23017 to indicate what the resistors are. Maybe I’m just not understanding what I’m trying to look for… As I mentioned, I’m just looking for something thorough about components, wiring , the resistors, why people have or don’t have it… I have a pisound , and the post that sounds helpful about the pisound , the dude knew what he was looking for and didn’t really explain much .

Im not sure I get where something I need is hiding… I expand the code on GitHub but I’m lost. I spent many hours on the wiki, and short of what I need to find. I do know once I connect everything, I may need to reconfigure the pins on the webconf, but that is it.

Hi @slimpyman

It sounds like you are a novice with electronics. You may wish to consider a simpler project to start your engineering adventure. My foray into this world started with a lamp and a battery and progressed rapidly through resistors, transistors, capacitors, ICs, inductors, etc. Within weeks I was building complex circuits and within months designing my own. That was more than 40 years ago and I have probably forgotten much of what I have learned but you do need to start at the beginning.

If you want to experience Zynthian in all of its glory with minimal engineering experience then the kit of parts is the best place to begin. It does not involve any design or soldering, just plug it together. If the kit is unavailable (maybe due to world shortage of components) then you may wish to build a very simple Zynthian without the extra electronic hardware, e.g. without encoders then in parallel learn the basics of electronics. I am sure you will be able to gain sufficient understanding pretty quickly of circuit diagrams and how that relates to putting a more complex Zynthian together.

Zynthian kits are aimed at the technically minded user who does not have engineering skills. DIY Zynthian (not from a kit) is within the realms of the more experienced electronic hobbyist.

Good luck. A little perseverance will get you a long way if you follow the right path (or not too many dead ends!).

You could also try installing kicad in your computer … :wink: